Carburetor



Oct. 31, 1967 R. R. HILL 3,350,073

' CARBURETOR Filed Nov. 1.5, 1965 2 Sheets-Sheet l I INVENTOR. Ammo/v0P0615? H/LL BY F I 5-- 2 @M/ FM ATTOENEVS R. R. H l L L CARBURETOR Oct.31, 1967 2 Sheets-Sheet 2 Filed Nov. 15, 1965 FIE- FIE--4;

INVENTOR. RA VMOA/D 065.? HILL ATTORNEYS 3,350,073 CARBURETOR Raymond R.Hill, 11 White Cottage Road,

- Angwin, Calif. 94508 Filed Nov. 15, 1965, Ser. No. 507,752 3 Claims.(Cl. 261-44) ABSTRACT OF THE DISCLOSURE A fuel injection carburetorhaving a variable venturi defined by a sliding valve door and having avacuum operated fuel valve for automatically closing off the fuel supplywhen the engine is turned off.

Summary of invention This invention relates to carburetors for internalcombustion engines and more particularly to improvements in fuelinjection carburetors of the type shown in my US. Patent No. 3,182,974which was issued on May 11, 1965.

My above mentioned patent shows fuel injection carburetors in which avalve door moves responsive to increasing demand for fuel-air mixture toprovide a variable venturi, and fuel is discharged into the variableventuri by a fuel discharge mechanism which distributes the fueluniformly over the area of the venturi. Additionally, the carburetorsshown in my above mentioned patent provide a vacuum biasing means whichautomatically adjusts the richness of the fuel-air mixture so that themixture is more lean under cruising conditions than it is underacceleration conditions.

In accordance with this invention, I have provided an improvedcarburetor of the same general type as that shown in my patent, but theimproved carburetor employs a sliding door for the mixing chamber withthe door opening in response to the requirements of the carburetor forincreased fuel-air mixture, and I have provided an automatic vacuumshut-off valve which closes off the fuel supply for the carburetorimmediately when the engine is turned off and prevents flooding of thecarburetor by fuel leakage after the engine has been turned oif.

Other objects and advantages of the invention will become apparent fromthe following description read in conjunction with the attached drawingsin which:

FIG. 1 is an elevation view of a carburetor constructed in accordancewith the principles of this invention;

FIG. 2 is a vertical section view of the carburetor of FIG. 1;

FIG. 3 is a top plan view of the carburetor of FIG. 1;

FIG. 4 is a cross-sectional view of FIG. 2 taken along plane 4 4.

Referring now in detail to the drawings and particularly .to FIG. 1, thecarburetor in general is indicated by the numeral 10. The carburetor 10is shown in FIG. 1 as mounted on an intake manifold 12 secured theretoby bolts 13.

Referring now to FIG. 2, a vacuum chamber 14 is separated from a mixingchamber 16 by a butterfly valve 18. The buterfly valve 18 is mounted onaxle 20 which is rotatable within axle bearings 22.

The top wall of the mixing chamber 16 is formed by a valve door 24 whichis slidable along the upper portion of the mixing chamber 26. The valvedoor 24 has a slanted portion 25 and a flat portion 27. The valve door24 forms an opening 23 with a front wall 29 of the mixing chamber 16through which air passes as the door moves to its open position. Asindicated in the drawings, the slanted portion 25 and the surroundingportions of the body are rectangular, but they may take other shapes.

. United States Patent Mounted on the valve door 24 are valve doorbearing blocks 28 and 30 supporting a Teflon sleeve bearing 31 slidableon a rod 32. Rod 32 is secured on the carburetor body by means of snaprings 34. A Teflon ring 36 and a cylindrical sleeve 38 act as a stopagainst bearing block 30 when the valve door 24 is in its closedposition as indicated in phantom. A finger 40 is mounted on a pivotshaft 42 and extends through the plug 43 pivotally mounted in bearingblock 30. The finger 40 biases the valve door 24 towards the closedposition as explained later.

Sleeve 44 is connected to the valve door 24 at point 46. The sleevereceives a metering rod 48 from one end and has a piston 50 mounted onits opposite end by snap rings 51. The piston 50 is mounted inside of acylinder 52 which is in turn mounted in the carburetor body. A seal 54closes off the cylinder 52 from the mixing chamber 16. A vacuum intakepassageway 5 6 communicates with the Vacuum chamber 14 and opens intothe cylinder 52. The cylinder 52 is opened to the air at the oppositeend from seal 54. Thus, piston 50 is subjected to the differences inpressure between the outside air pressure and the pressure in the vacuumchamber 14. Where desirable, the other end of the cylinder may beconnected to the mixing chamber to subject the piston to the pressuredifferential across the butterfly valve 18, but more pronounced responseof the piston to the vacuum in the vacuum chamber is obtained with thearrangement illustrated.

The metering tube 48 has a bore 58 which is opened to the mixing chamber16 through a series of fuel supply ports 60. Set screw 62 has a conicalhead such that the set screw 62 may be adjusted to force the meteringtube into the mixing chamber 16. The spring 64 biases the metering tube48 away from the mixing chamber 16 and against the set screw 62.

A fuel shut off valve is indicated generally as 66 and has a housingwith an upper portion 68 and a lower portion 69 fastened together bybolts 71 (see FIG. 1). The upper portion of the housing 68 has anopening at 70 adapted to be connected to a fuel pump for supplying fuelto the housing 68 from the tube 72, and an opening at 74 for dischargingfuel to the metering tube 48. A plunger 78 having a rubber gasket 82 isbiased by the spring 7 6 down against the inner sleeve 80 with theplunger 7'8 and sleeve 80 having valve seats 79 and 81 respectively. Apiston 84 having a flange 85 fits within a retaining plug 86 and restsupon a diaphragm 88. A vacuum intake port 90 communicates with thevacuum chamber 14 and opens into a chamber 91 of the housing 68 throughan aperture 92.

In the lower portion of the housing 69 (FIG. 2) the axle 22 of thebutterfly valve has a flat portion 94 which contacts a lower piston 96.An air port 98 communicating with the outside empties into a ring 100below the diaphragm 88.

Referring now to FIGS. 3 and 4, back-fire ports 102 are shown covered byplate 104 which is fastened to the valve door 24 by bolts 106. Clip 108restricts the plate 104 in case of back fire. The biasing finger 40 ismounted on the shaft 42 such that when the valve door 24 moves to anopen position the shaft 42 .will rotate in a counterclockwise directionas viewed in FIG. 1. Opposing this counterclockwise rotation is a spring110* which is secured at one end to arm 1-12 and at the other end to arm.114 mounted on the shaft 42. The arm 112 fits Within a hole 116 in themounting 118. Set screw 120 may be loosened to allow the arm 112 to beset in any given position within the mounting 118. Arm 114 fi'ts withina hole 122 in the shaft 42. Set screw 124 may be loosened to allow thearm 114 to be set in any given position within the shaft 42. A weight12.6 is mounted on the arm 128 and may be positioned any place along thearm 128 by loosening the set screw 130. The weight 126 and the arm 128combine to bias the shaft against clockwise rotation. Thus, adjustmentof arms 112 and 114 and positioning of weight 126 combine to influencethe biasing effect on the shaft 42 which in turn effects the biasingforce of the finger 40 upon the valve door 24.

The operation of the carburetor will now be explained. When the engineis started, the axle 20 is turned thus moving the butterfly valve 18 toan open position. The flat portion of the axle 94 pushes the lowerpiston 96 up against the diaphram 88, piston 84, and plunger 78 topermit the fuel to flow from the tube 72 through the inner sleeve 80 andout through the opening 74 to the metering tube 48. After the engine hasbegun to operate a vacuum is created in the vacuum chamber 14 which iscommunicated by the vacuum intake port 90 to the chamber 91. Since thering 100 is at atmospheric pressure, due to air port 98, the diaphram isurged up against piston 84 and plunger 78. Thus, the difference inatmospheric pressure and the pressure in the vacuum chamber 14 holds theplunger 78 open to allow fuel to travel to the metering tube 48.

When the engine associated with the carburetor is in its idlingcondition a relatively strong vacuum is created in chamber 14 by thefluid demands of the engine. A very small minimum clearance adjustablefor adjusting idling speed is provided between the periphery of thebutterfly valve 18 and the adjacent Walls of the carburetor 10 to permitjust sufficient fuel air mixture to pass therethrough to supply theidling requirements of the engine.

Under this idling condition, air enters the carburetor through theopening 23 and a small amount of fuel enters chamber 16 through the fuelsupply ports 60 and the metering tube 48. The quantity of fuel suppliedunder idling conditions can be changed by adjusting screw 62 which willmove the metering tube 48, thereby adjusting the number of fuel supply.ports 60 which are not covered by the sleeve 44. The interior of thesleeve at the right hand end shown in FIG. 2 is tapered over an areaspanning several of the ports 60 so that movement of the sleeve on themetering tube causes a uniform change in fuel supply instead of anabrupt change.

When it is desirable to accelerate the engine on which the carburetor isemployed butterfly valve 18 is opened by turning axle 20, therebydrawing fluid from the chamber 16 into ohamber 14 responsive to thepressure gradient across butterfly valve 18. When this flow of fluid outof chamber 16 causes a reduction in pressure in chamber 16 relative toatmospheric pressure which is applied to the upper side of the slantedportion of the door 25, the door 24 is accordingly pushed by componentforce to an open position in opposition to biasing spring 110. As door25 moves to an open position it provides a generally rectangular opening23 between the edge of the door and the front wall 29. The airrequirements of the engine are drawn into chamber 16 through thisopening. As door 24 moves to the open position, it also moves sleeve 44thereby exposing additional fuel supply ports 60 in the metering tube48. The additional fuel requirements of the engine are supplied throughthese additional exposed fuel supply ports 60.

It will be noted that the exposed fuel supply ports 60 are provided on aline which extends generally centrally through the opening between thefree edge of the door 24 and the front wall 29 of the chamber 16. Thisposition of fuel supply ports 60 at the vortex of the airstream enteringthe carburetor 10, coupled with the fact that the fuel supply ports 60are directed laterally towards the ends of the opening 25 produces themaximum evaporation of fuel supplied from the fuel supply ports and themaximum uniformity of fuel air mixture produced by such evaporation.Further, the fact that additional fuel supply ports are exposed for eachincremental increase in the size of the opening between valve door 24and the front wall 29 insures that this uniformity of fuel air mixtureis maintained regardless of the position of the valve door 24 and thequantity of air passing through the opening between valve door 24 andfront Wall 29.

It should be noted that the line of action of tension spring withrespect to the axis of arm 114 forms an acute angle which decreasestowards zero degrees as door 24 opens, thus providing a reduction in theworking arm of spring 110 as the door 24 is opened and the spring 110 isstretched.

When it is desirable to stop the engine on which the carburetor isemployed, butterfly valve 18 is closed by manipulating the axle 20 tothe idling position of the butterfly valve, thereby permitting the shutoff 66 valve of the carburetor to close. The rotation of the axle 20permits the lower piston 96 to drop back in its lower position. When theignition is turned off to stop the engines demand for fuel from thechamber 14, the pressure in chamber 14 rises to atmospheric pressure andthe pressure in chamber 91 also assumes atmospheric pressure. Thisresults in the diaphragm 88 returning to its down position, and thepiston 84 no longer being forced up against the plunger 78.Consequently, 78 is biased downwardly by the resilient spring 76 therebyclosing off the flow of fuel through the inner sleeve 80. The foregoingreaction of the various components occurs instantaneously when thebutterfly valve 18 is closed and the ignition turned off therebypreventing the flow of fuel into chamber 16 and a consequential floodingof the engine.

The effect of the operation of the piston cylinder combination, 50 and52, is to provide more adequate control of the opening and closing ofthe valve door 25 as it is opened to a greater extent and to providemore immediate response of the valve door 24 to the closing of butterflyvalve 18. Thus, atmospheric pressure applied to the outer side of piston50 cooperates with low pressure in the vacuum chamber 14 to apply anadditional biasing force to sleeve 44 tending to close the valve door 24responsive to increase in the vacuum in chamber 14.

The piston cylinder combination, 50 and 52, automatically adjust thecarburetor to provide different richness of fuel air mixture atdifferent operating conditions of the engine. Thus, under cruisingconditions, when the engine is running rapidly and the butterfly valve18 is positioned in an intermediate, partially closed, position, arelatively high vacuum exists in the vacuum chamber 14. This high vacuumapplied to the piston cylinder combination, 50 and 52, biases the valvedoor 24 towards more closed position than it would occupy if the pistoncylinder combination, 50 and 52, were not present; this partial closingof the valve door 24 reduces the fuel supply ports 60 by closing offsome ports without causing a corresponding reduction in the volume ofair flowing past the valve door. In this Way, the piston cylindercombination causes a leaning of the fuel air mixture during cruisingconditions; however, when the butterfly valve 18 is opened Wide foracceleration conditions of the engine, the vacuum chamber 14 is placedin more direct communication with the atmosphere; the degree of vacuumin the vacuum chamber is reduced, and the fuel air mixture becomesricher because the biasing effect of the piston cylinder combination isreduced.

As indicated above, the provision of many adjusting screws permitsmaximum adjustment of the carburetor to suit various environments.

The mixing chamber 16 while shown to be rectangular in shape can be madeto any desired configuration. Thus, if it is desired the mixing chamber16 can be formed in the shape of a trapezoid which would require, ofcourse, that the valve door 24 be shaped similarly.

While the above description on the attached drawings describes onespecific embodiment of the invention, it is apparent that the carburetorof the invention may be constructed with many modifications anddimensions, ar-

rangements of parts, and omission and addition of parts Withoutdeparting from the spirit and scope of the invention.

I claim:

1. In a carburetor comprising a carburetor body defining at least inpart a vacuum chamber adapted to communicate with the intake manifold ofan internal combustion engine and a fuel mixing chamber, and adjustablevalve means for providing variable communication between the vacuumchamber and the mixing chamber, improved means for introducing fuel andair into the mixing chamber comprising:

(A) a valve door having a flat top portion and an inclined side portion,said door having an edge on said inclined portion adjacent to said bodydefining with said body an opening into said mixing chamber, meansincluding bearings mounting said door for sliding movement on said bodyalong flat portion responsive to air pressure on said inclined portionwhereby said opening increases responsive to increasing vacuum in saidmixing chamber,

(B) a metering tube located within the mixing chamber having,

(1) an axial bore adapted to be connected to a source of fuel, and

(2) discharge means communicating with the bore and having a fluiddischarge area distributed along the length of the tube for introducingfuel into the mixing chamber,

(C) sleeve means slidable receiving the metering tube, with the sleeevemounted on said valve door for movement with the valve door to an openposition responsive to increasing vacuum in the mixing chamber therebyexposing an increasing amount of the fuel discharge area of the meteringtube as the door opens, and

(D) resilient means biasing the door to a closed position.

2. The apparatus of claim 1 characterized further by the inclusion of(A) a fuel shut off valve comprising (1) a housing,

(2) means for supplying fuel to the housing,

(3) means for discharging fuel from the housing into the mixing chamber,

(4) plunger means located within the housing having a closed positionpreventing the flow of fuel through the housing and an open positionpermitting the flow of fuel through the hous- (5) resilient meansbiasing the plunger toward the closed position, and

(6) vacuum biasing means communicating with the vacuum chamber andbiasing the plunger to an open position, and

(B) mechanical means interconnecting the adjustable valve means and theshut off valve for permitting the plunger to move to its closed positiononly when the adjustable valve means is closed.

3. In a fuel injection carburetor comprising a carburetor body definingat least in part a vacuum chamber adapted to communicate with the intakemanifold of an internal combustion engine and a fuel mixing chamber andadjustable valve means having a closed position and defining at least inpart one air passageway to the vacuum chamber for admitting air to theintake manifold, improved means for introducing fuel and air into themixing chamber comprising: a valve door forming a wall of the mixingchamber and means mounting said valve door for movement responsive toincreasing vacuum in the mixing chamber to provide an opening ofincreasing size in the Wall of the mixing chamber, a metering tubelocated within the mixing chamber having, an axial bore and dischargemeans communicating with the bore and having a fluid discharge areadistributed along the length of the tube for introducing fuel into themixing chamber,

(A) a housing,

(B) means for supplying fuel to the housing,

(C) means for discharging the fuel from the housing into the meteringtube,

(D) plunger means located Within the housing having a closed positionpreventing the flow of fuel through the housing and an open positionpermitting the flow of fuel through the housing,

(E) resilient means biasing the plunger towards the closed position,

(F) vacuum biasing means communicating with the vacuum chamber andbiasing the plunger to an open position, and

(G) mechanical means interconnecting the plunger and the adjustablevalve means for permitting the plunger to move to its closed positiononly when the adjustable valve means is in closed position.

References Cited UNITED STATES PATENTS 10/ 1921 Henderson 261-49 X6/1924 Hansen-Ellehammer.

12/ 1930 Atkins.

5/ 1965 Hill.

50 HARRY B. THORNTON, Primary Examiner.

RONALD R. WEAVER, Examiner.

1. IN A CARBURETOR COMPRISING A CARBURETOR BODY DEFINING AT LEAST INPART A VACUUM CHAMBER ADAPTED TO COMMUNICATE WITH THE INTAKE MANIFOLD OFAN INTERNAL COMBUSTION ENGINE AND A FUEL MIXING CHAMBER, AND ADJUSTABLEVALVE MEANS FOR PROVIDING VARIABLE COMMUNICATION BETWEEN THE VACUUMCHAMBER AND THE MIXING CHAMBER, IMPROVED MEANS FOR INTRODUCING FUEL ANDAIR INTO THE MIXING CHAMBER COMPRISING: (A) A VALVE DOOR HAVING A FLATTOP PORTION AND AN INCLINED SIDE PORTION, SAID DOOR HAVING AN EDGE ONSAID INCLINED PORTION ADJACENT TO SAID BODY DEFINING WITH SAID BODY ANOPENING INTO SAID MIXING CHAMBER, MEANS INCLUDING BEARINGS MOUNTING SAIDDOOR FOR SLIDING MOVEMENT ON SAID BODY ALONG FLAT PORTION RESPONSIVE TOAIR PRESSURE ON SAID INCLINED PORTION WHEREBY SAID OPENING INCREASESRESPONSIVE TO INCREASING VACUUM IN SAID MIXING CHAMBER, (B) A METERINGTUBE LOCATED WITHIN THE MIXING CHAMBER HAVING, (1) AN AXIAL BORE ADAPTEDTO BE CONNECTED TO A SOURCE OF FUEL, AND (2) DISCHARGE MEANSCOMMUNICATING WITH THE BORE AND HAVING A FLUID DISCHARGE AREADISTRIBUTED ALONG THE LENGTH OF THE TUBE FOR INTRODUCING FUEL INTO THEMIXING CHAMBER, (C) A SLEEVE MEANS SLIDABLE RECEIVING THE METERING TUBE,WITH THE SLEEVE MOUNTED ON SAID VALVE DOOR FOR MOVEMENT WITH THE VALVEDOOR TO AN OPEN POSITION RESPONSIVE TO INCREASING VACUUM IN THE MIXINGCHAMBER THEREBY EXPOSING AN INCREASING AMOUNT OF THE FUEL DISCHARGE AREAOF THE METERING TUBE AS THE DOOR OPENS, AND (D) RESILIENT MEANS BIASINGTHE DOOR TO A CLOSED POSITION.